Now if you run $ php -v, you will get PHP 5.5 or something. This is the default PHP version that is shipped with OSX and cannot be removed. You just need to edit your path to ensure that PHP 7.0 is picked up.

export PATH="$(brew --prefix homebrew/php/php70)/bin:$PATH"

To debug any issue with any package, you can run brew info php70 etc.

Also, if you are getting seemingly unrelated errors, make sure to update bash/zsh: brew upgrade bash and brew upgrade zsh.

If everything is setup correctly, running $ php -v should give you 7.0.+.